Celestron NexStar 8i, Instruction Manual

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Optical Specification
NexStar 5i NexStar 8i
Design Schmidt-Cassegrain Catadioptric Schmidt-Cassegrain Catadioptric
Aperture 5 inches (127mm) 8 inches (203.2mm)
Focal Length 50 inches (1250mm) 80 inches (2032mm)
F/ratio of the Optical System 10 10
Primary Mirror: Material
Coatings Fine Annealed Pyrex
Starbright Coatings - 5 step multilayer
process Fine Annealed Pyrex
Starbright Coatings - 5 step multilayer
process
Secondary Mirror: Material
Coatings Hand Figured Fine Annealed Pyrex
Starbright Coatings - 5 step multilayer
process Hand Figured Fine Annealed Pyrex
Starbright Coatings - 5 step multilayer
process
Central Obstruction 2” (16% by area) 2.5” (10% by area)
Corrector Plate: Material
Coatings Optical Quality Soda Lime
MgF2 Coatings both sides Optical Quality Crown Glass
MgF2 Coatings both sides
Highest Useful Magnification 300x ( ~ 4mm eyepiece) 480x ( ~ 4mm eyepiece)
Lowest Useful Magnification (7mm
exit pupil) 18x ( ~ 70mm eyepiece)
29x ( ~ 70mm eyepiece)
Resolution: Rayleigh Criterion
Dawes Limit 1.1 arc seconds
.91 arc seconds .68 arc seconds
.57arc seconds
Photographic Resolution 200 lines/mm 200 lines/mm
Light Gathering Power 329x unaided eye 843x unaided eye
Near Focus standard eyepiece or
camera ~ 20 feet ~ 25 feet
Field of View: Standard Eyepiece
: 35mm Camera 1.04º
1.6º x 1.1º (2.5º x 1.75º - with optional
Reducer Corrector) .64º
1.0º x .68º (1.6º x 1.07º - with optional
Reducer Corrector)
Linear Field of View (at 1000 yds) 55 feet 34 feet
Magnification: Standard Eyepiece
: Camera 50x
25x 81x
41x
Optical Tube Length 11 inches 17 inches
Weight of Telescope 17.6 Lbs. 24 Lbs.
Electronic Specifications
Input Voltage
Maximum
Minimum 12 V DC Nominal
18 V DC Max.
8 V DC Min.
Batteries Required 8 AA Alkaline
Power Supply Requirements 12 VDC-750 mA (Tip positive)
Mechanical Specifications
Motor: Type
Resolution DC Servo motors with encoders, both axes
.26 arc sec in Azimuth, .32 arc sec in altitude
Fork Arm Cast aluminum, with integrated hand control receptacle
Electronic Hand Control Specifications
Slew speeds Six slew speeds: 6º /sec, 2º /sec, 128x, 64x, 16x, 8x
Tracking Modes Alt-Az, EQ North, EQ South , Off
Optional Computerized Hand Control Specifications
Hand Control
Double line, 16 character Liquid Crystal Display
19 fiber optic backlit LED buttons
Slew speeds Nine slew speeds: 6º /sec, 3º /sec, 1.5º/sec, 128x, 64x, 16x, 8x, 2x, 1x
Software Precision 24bit, 0.08 arcsec
calculations
Ports RS-232 communication port on hand control
Tracking Rates Sidereal, Solar and Lunar
Tracking Modes Alt-Az, EQ North & EQ South
Alignment Procedures 2-Star Alignment, AutoAlign, EQ North/South and GPS Align (with
optional CN16 GPS Accessory)